On Tuesday, November 29, 2016, Nathaniel Smith
On Tue, Nov 29, 2016 at 1:05 AM, Victor Stinner
javascript:;> wrote: Hi,
Python is optimized for performance. Formatting an error message has a cost on performances.
Sure, but we have to look at this on a case-by-case basis. Is there really important code out there that's generating NameErrors or SyntaxErrors in an inner loop? That seems unlikely to me.
Even IndexError I'm a bit skeptical about. I can believe that there's code that intentionally generates and then catches IndexError, but AttributeError in my experience is much more performance-sensitive than IndexError, because every failed hasattr call allocates an AttributeError and hasattr is commonly used for feature checks. Yet AttributeError has a much more informative (= expensive) message than IndexError:
In [1]: object().a AttributeError: 'object' object has no attribute 'a'
In [2]: list()[0] IndexError: list index out of range
https://docs.python.org/2/tutorial/datastructures.html#more-on-lists https://docs.python.org/2/c-api/list.html#c.PyList_SetItem https://github.com/python/cpython/search?utf8=✓&q=PyList_SetItem - https://github.com/python/cpython/blob/master/Include/listobject.h - https://github.com/python/cpython/blob/master/Objects/listobject.c#L208 - https://hg.python.org/cpython/file/tip/Objects/listobject.c#l208 https://docs.python.org/3/library/collections.abc.html#collections-abstract-... - list (typeshed: List) - Sequence - MutableSequence - It would be great if these continue to match: https://www.google.com/search?q=IndexError%3A+list+index+out+of+range
-n
-- Nathaniel J. Smith -- https://vorpus.org _______________________________________________ Python-ideas mailing list Python-ideas@python.org javascript:; https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/